<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
	</head>
	<body>
		<canvas id="canvas" style="border: 1px solid red;"></canvas>
		<script type="text/javascript">
			var canvas = document.getElementById('canvas')
			var cxt = canvas.getContext('2d')
			canvas.width = 400
			canvas.height = 300
			for (var i = 0; i < 20; i++) {
				cxt.lineWidth = 1+i
				cxt.beginPath()
				cxt.moveTo(5+i*25, 5)
				cxt.lineTo(5+i*25, 140)
				cxt.stroke()
			}
		</script>
	</body>
</html>
